239 research outputs found
El traje tradicional en la comarca de Arenas de San Pedro: generalidades
En número dedicado a: Avila: Valle del Tiéta
Criptografía Cuántica en Redes Clásicas
Quantum Key Distribution (QKD) is the first technology derived from Quantum Information and Quantum Computation that is being marketed. To date, the commercial applications are in the encryption of point to point links. Now, the next logical step is about to be taken. Full quantum networks able to transport the keys to be used in symmetric key cryptography with a security level previously unattained are being designed. The proof of concept of many of the ingredients needed exist and networks with a few nodes have been implemented. The first networks will cover a metropolitan area and demonstrate the feasibility of large-scale QKD integrated with classical networks. If it succeeds in the marketplace, this could signal a major shift in how cryptography is used today
Integrando la criptografía cuántica en redes clásicas
En este artículo discutimos las limitaciones y ventajas de la distribución cuántica de claves y los primeros pasos hacia su inclusión dentro de la infraestructura de seguridad en las redes de comunicaciones convencionales
Information reconciliation for Quantum Key Distribution
Secret-key agreement, a well-known problem in cryptography, allows two parties holding correlated sequences to agree on a secret key communicating over a public channel. It is usually divided into three different procedures: advantage distillation, information reconciliation and privacy amplification. The efficiency of each one of these procedures is needed if a positive key rate is to be attained from the legitimate parties? correlated sequences. Quantum key distribution (QKD) allows the two parties to obtain correlated sequences, provided that they have access to an authenticated channel. The new generation of QKD devices is able to work at higher speeds and in noisier or more absorbing environments. This exposes the weaknesses of current information reconciliation protocols, a key component to their performance. Here we present a new protocol based in low-density parity-check (LDPC) codes that presents the advantages of low interactivity, rate adaptability and high efficiency,characteristics that make it highly suitable for next generation QKD devices
Protocolos de reconciliación de información óptimos y no interactivos para distribución cuántica de claves
Propuesta de protocolos de reconciliación de información basados en códigos LDPC no interactivos aplicados a la distribución cuántica de claves
On QKD industrialization
During the 25 years of existence of the first protocol for Quantum Key Distribution, much has been said and expected of what came to be termed as Quantum Cryptography. After all this time, much progress has been done but also the reality check and analysis that naturally comes with maturity is underway. A new panorama is emerging, and the way in which the challenges imposed by market requirements are tackled will determine the fate of Quantum Cryptography. The present paper attempts to frame a reasonable view on the issues of the security and market requirements that QKD should achieve to become a marketable technology
Reconciliación de errores mínimamente interactiva en distribución cuántica de claves
Algunos trabajos recientes han desarrollado varias alternativas a Cascade, entre las cuales destacan aquellas basadas en el uso de técnicas de codificación modernas. Por ejemplo, a través del uso de códigos Low-Density Parity-Check (LDPC) hoy día encontramos varias propuestas que permiten mejorar la eficiencia de la reconciliación de clave para ratios de error elevados. Al utilizar códigos LDPC tan sólo se requiere un único uso del canal de comunicación. Estas propuestas se basan en una técnica conocida como “codificación de síndrome” que permite aplicar métodos de corrección de errores para reconciliar cadenas aleatorias correlacionadas. En una de estas propuestas aplicamos dos técnicas conocidas en codificación, cómo son la perforación y el acortado de símbolos, para adaptar en tiempo real el ratio de información proporcionado por el síndrome intercambiado
Extractive distillation with ionic liquids to separate benzene, toluene, and xylene from pyrolysis gasoline: process design and techno-economic comparison with the morphylane process
Aromatic/aliphatic separation stands as a challenge for both industry and academia. More and more efforts are being made to improve energy-demanding technologies based on liquid–liquid extraction or extractive distillation processes. Recently, ionic liquid-based technologies devoted to separating benzene, toluene, and xylene from pyrolysis gasoline have been evaluated, and extractive distillation showed more potential than liquid–liquid extraction in terms of separation performance and global energy requirements. In this work, extractive distillation with ionic liquids is completely evaluated from solvent selection to rate-based process design and compared with the Morphylane benchmark process. The ILUAM database is explored through a validated COSMO/Aspen methodology to understand the impact of the ionic liquid nature on the extractive distillation operation. A parametric study focused on the extractive distillation column (EDC) is conducted for preliminary set initial guesses to design task. The final issue is centered on rigorously designing the ionic liquid-based and Morphylane processes at commercial specifications. Two different ionic liquid-based process configurations are evaluated based on the opportunities that the use of ionic liquids enables. The new process configuration working with [emim][TCM] reduces the energy costs and capital expenditures associated with the Morphylane process by 67 and 63%, respectively, along with a reduction in the solvent costs, confirming it as a cleaner alternative. In addition, a parametrization of the Cubic Plus Association equation of state (CPA EoS) obtained from the regression of experimental vapor–liquid–liquid equilibrium data is also used to simulate the EDC in equilibrium and rate-based mode. Both models provide similar results, confirming the ability of the conductor-like screening model–segment activity coefficient model as an a priori tool and the reliability of the CPA EoS as a regressive alternative to describe these kinds of complex multicomponent systemsThe authors are grateful to Comunidad de Madrid (project P2018/EMT4348) and Ministerio de Economía y Competividad (MINECO) of Spain (projects CTQ2017-85340, CTQ2017-89441-R, and PID2020-118259RB-I00) for its financial support and Centro de Computación Científica de la Universidad Autónoma de Madrid (CCC) for its computational ́ resources. Miguel Ayuso also thanks Ministerio de Ciencia Innovación y Universidades for awarding him an FPI grant (PRE2018-083728
Análisis bibliométrico de la producción científica sobre la adaptación a la vida universitaria.
La adaptación a la vida universitaria representa un gran desafío para los jóvenes. Dadas las nuevas dificultades que se añaden a este reto como consecuencia del COVID-19, el objetivo de este estudio es analizar la producción científica sobre esta cuestión de las últimas tres décadas (1991-2021). Para ello, se ha combinado el estudio bibliométrico con técnicas de análisis de redes sociales a través de los softwares Rstudio y Vosviewer. Se han analizado 291 artículos procedentes de la base de datos Scopus. Los resultados permiten obtener una visión holística de este campo y de su evolución a lo largo del tiempo.post-print2432 K
Bio-inspired computational memory model of the Hippocampus: an approach to a neuromorphic spike-based Content-Addressable Memory
The brain has computational capabilities that surpass those of modern
systems, being able to solve complex problems efficiently in a simple way.
Neuromorphic engineering aims to mimic biology in order to develop new systems
capable of incorporating such capabilities. Bio-inspired learning systems
continue to be a challenge that must be solved, and much work needs to be done
in this regard. Among all brain regions, the hippocampus stands out as an
autoassociative short-term memory with the capacity to learn and recall
memories from any fragment of them. These characteristics make the hippocampus
an ideal candidate for developing bio-inspired learning systems that, in
addition, resemble content-addressable memories. Therefore, in this work we
propose a bio-inspired spiking content-addressable memory model based on the
CA3 region of the hippocampus with the ability to learn, forget and recall
memories, both orthogonal and non-orthogonal, from any fragment of them. The
model was implemented on the SpiNNaker hardware platform using Spiking Neural
Networks. A set of experiments based on functional, stress and applicability
tests were performed to demonstrate its correct functioning. This work presents
the first hardware implementation of a fully-functional bio-inspired spiking
hippocampal content-addressable memory model, paving the way for the
development of future more complex neuromorphic systems.Comment: 15 pages, 5 figures, journal, Spiking Neural Networ
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